[1] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Cardiac Arrhythmia Serv, Boston, MA 02115 USA
[2] Harvard Univ, Sch Med, Massachusetts Gen Hosp, Heart Failure Serv,Div Cardiol, Boston, MA USA
[3] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Div Oncol,Dept Med, Boston, MA USA